Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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MATRIX DISPLAY STEREOSCOPIC SYSl7EM
PIELD OF THE INVEN rION
The invention pertains to stereoscopic matrix displays.
Pa~icularly, the invention pertains to color matrix display non-field-
sequential stereoscopic display systerns.
B~CKGROUND QE THE IN~i/ENT~ON
Stereoscopic displays, even color displays, have been in the
related art for some time. Some systems involve cathode-ray tube (CRT)
based, field-sequential stereoscopic display systems. Existing CRT-based
field-sequential systems, which utilize cross-polarization, have inter-ocular
cross talk which is due to timing and sychronization problems. Horizontal
offset in raster CRT or other based systems is typically limited by constraints
on horizontal addressability imposed by the effective honzontal resolution of
the CRT. Small vertical offsets are inherent in field-sequential stereoscopic
display systems due to the fact that the left and right eye views are presenteclon alternating, inter-laced fields.
SUMMARY C)F THE INVEN~ION
The invention may utilize color matrix displays. Each display
provides the full frame of the right eye and left eye views, in other words,
the displays are not field-sequential. The images are optically combined in
an elegant manner to be projected to the viewer as ~ight and left circular
polarized images combined as one. The viewer can see full-color
stereoscopic images with a set of simple, inexpensive circularly polarized
2S glasses. Because the system is not field-sequential, it does not have to be
time-rnultiplexed. The circularly polarized left and right eye images are
simultaneously presented to each eye with the full resolution the displays
would have in full~frame nonstereo operation.
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The present invention's combining of the two matrix d;splay
images enable the use of gray scale techniques without the problems caused
by correlations between the gray scales and direct off-axis viewing of the
matrix display panels. A gray scale may be used in the present system to
5 anti-alias the images on each of the two panels and provide a level of
subpixel addressab;lity which can enable very fine-grained and precise
positioning of the disparate points within the two eye images relative to each
other. Since human stereoscopic acuity is hyperacute (i.e., on the order of
five arc seeonds), the extremely fine horizontal offsets between the left-eye
10 image points and the right-eye image points which can be provided by
subpixel addressability, may be used to greatly enhance s~ereoscopic visual
performance. It is addressability which performs this function and such
stereoscopic enhancement is not directly dependent on the resolution of the
matrix display panels.
The present invention virtually eliminates vertical offsets
between the left eye and right eye images because of the lack of alternating
inter-laced fields.
The present system may utilize flexible, advanced display
processor techniques. For instance, a separate processor may be allocated to
20 simultaneously generate the images for each eye in parallel. The invention
takes advantage of the inherent linear polariza~ion of matrix displays and
combines the images into one, but each view having a particular cir ular
polarization. Viewing stereoscopic images which utilize circular polarization
allows one to rotate the head without suddenly loosing the stereoscopie
25 effect, and reduces light aberrations that appear with linear polarization
viewing systems in places such as aircraf~ cockpits.
For viewing images with the invention, the field lens
implementation or the projection approach may be used. With the field lens
irnplementation, the observer views a stereoscopic virtual image. There are
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two advantages of this implementation. First, the system is then rslatively
immune to diffuse and specular reflections ansing from sources of ambient
illumination in the viewing environment. Second, a stereoscopic virtual
image illuminates the perception of a fixed image plane (i.e., the display
S surface) and a fixed reference for a visual accommodation and binocular
vergence and results in enhanced depth perception and stereoscopic display
performance.
For the projection approach in the present system, the
stereoscopic display allows flexibility in the synthesis of a multi-color image.It is possible to separate color image components such as the short-
wavelength image components (which contribute little or nothing to human
spatial resolution or to the processing of stereoscopic visual information) and
to present them at a much lower resolution than the medium (green) and long
(red) wavelength components. This provides for higher resolution matrix
displays which require only red and green pixels, separately and
rçspectively, for the two primary image sources, while utilizing a single,
much lower resolution monochromatic blue panel as a common color
rendering source for both eye views.
BRIEF DESCRIPrION OF THE DRAWING
Figure 1 shows the basic configuration for a steresscopic
display system utilizing dual matrix display image sources.
Figure 2 reveals an alternate configuration of the stereoscopic
display system.
DESCRlPIION O~ THE PREFERRED EMBODIMENT
Figure 1 illustrates the basic concept of system 10. The left-
eye images are presented by a 1024 x 1024 element color liquid ~rystal
matnx display 12. Likewise, the right eye images are presented by a 1024 x
1024 color liquid crystal matrix display 14. Displays 12 and 14 have back
light units 16 and 18, respectively. The left and right images are provided to
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matrix displays 12 and 14, respectively, from left image processor 20 and
right image processor 22. Processors 20 and 22 have great flexibility when
generating left and right images. The images may be conversions of analog
signals conveying the left and right images from a camera or video storage
5 device, or may modify incoming images thereby providing special effects.
Also, the processors 20 and ~ may generate images of various sorts
intended to accornplish certain objectives for the viewer.
The components and functional aspects of system 10 are
described in the following. Structurally, an example layout would be like
that of ~igure 1 where displays 12 and 14 are positioned orthogonal to each
other and having a combiner 26 at a 45 degree angle and extending from a
corner where the displays 12 and 14 are closest to each other. Light beam
24 from left image matrix display 12 has a linear polarization of a first (e.g.,vertical) orientation which impinges polarized beam combiner 26 and is
15 reflected by combiner 26 as beam 28 with the same polarization and
orientation as beam 24. Beam 28 enters quarterwave plate 30 and e~its plate
30 as beam 32 having a first (e.g., le~t) circular polarization. Light beam 34
- exits right image matrix display 14, having the linear polarization of a first
orientation, like that of light beam 24. Light beam 34 passes through half
20 wave plate 38 and becomes light beam 36 having a linear polarization of a
second orientation (i.e., horizontal). Beam 36 passes through polarized
beam combiner 26 without any effect on its polarization and orientation.
Beam 36 passes through quarterwave plate 30 and becomes beam 4û having
a second (i.e., right~ circular polarization. Beams 32 and 40 of first and
25 second circular pola-rizations, respectively, present the left and right images.
Light beams 32 and 40 are conveyed by relay lens 4~ onto a Fresnel field
lens 44 for presenting stereoscopic virtual images, or to a non-depolarizing
screen 46 for projec~n of the images to the viewer. The viewer or obserYer
looks at the presented images through eye glasses having lenses 48 and 50.
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Lens 48 has a first circular polarization which permits light beam 32 to pass
through lens 48 to the viewer's left eye and blocks light beam 40 of the
secnnd circular polarization. On the other hand, lens 50 is of a second
polarization and perrnits the passing of light beam 40 of the second
S polarization and blocks light of beam 32 having a first circular polarization.Thus, the observer looking through the glasses can view color stereoscopic
images.
Figure 2 shows another embocliment 60 of the present
invention. The difference from embodiment 10 is that half-wave plate 38 is
10 absent. To aYoid use of plate 38, right image matrix display 14 is
constructed to have its linear polarization rotated 90 degrees. Then the light
from display 14 has the same linear polarization as beam 36.
Half-wave plate 38 may be positioned in front of left display 12
if display is reconstructed to have its linear polarization rotated 90 degrees
like that of display 14 in Figure 2. Or, as long as light beams 24 and 26
have different polarizations, the kind of polarization is immaterial as long as
the polarized beam combiner is designed to be tuned to the particular
polari~ation of the light beam desired to be reflected.
